The road of a PhD candidate can be long and troublesome. Data collection is always delayed, your paper gets rejected (again!), and an avalanche of student emails keeps clogging your inbox (and your mind). Many external factors can keep you from staying on track.
But face it; the biggest threat to finishing your dissertation on time is you.
Self-determination theory
A lack of motivation to finish your PhD project (or any other project for that matter) is not uncommon. But what triggers this (sometimes sudden) state of mind, and what can you do about it? According to Ryan and Deci’s self-determination theory (2000) there are three innate psychological needs that lay at the foundation of your motivation: autonomy, competence, and relatedness. Where all three needs are equally important, focusing on merely one or two of them seems unwise. (And you also have to keep in mind that there is such a thing as too much competence or too much autonomy.)
Therefore, you will have to find that sweet spot where your autonomy, competence, and relatedness toward the project intersect, helping you find your motivation to continue.
Autonomy
Autonomy is an important psychological need for staying motivated.
Whenever you feel like you have no autonomy and are being bossed around by your supervisor, or when completing a task that has been completely laid out for you, you might run the risk of losing motivation to finish it—or even worse: resist to it (see the work of Brehm on the reactance theory for more interesting insights into resistance).
You might look for your motivation outside of your project.By imagining the great pay you will have in a couple years, or the tenure you might land once this project is finished (or not. I mean, this is academia, who are we kidding right?). All of these things that you promise yourself, however, are uncertain, and in reality do not decrease the lack of motivation; you just find ways to deal with the lack of it.
A better way to deal with a loss in motivation is by claiming some degree of autonomy of the PhD; suggesting changes that you feel contribute, that you believe in, or even claiming the entire project itself. At the end of the day, it is your project, your brain that did most of the work. Be proud of it!
Keep in mind that you should look for the sweet spot. Too much autonomy can be problematic, just like too little: if you work fully autonomous this can constitute pressure to take it in the “right” direction, especially when full autonomy might be not supported by your environment (cq. your supervisor).
So if you feel like you have too much autonomy and do not know how to deal with it, ask your supervisor to constrain you to a certain topic or method, or even better: constrain yourself. If you have too little: do seize it.
Competence
Since you already have the PhD position, in theory you seemed competent enough to fulfill the task in the eyes of your supervisor(s). So hopefully a lack of competence is not your biggest hurdle.
Maybe equally problematic, but often overlooked, is being toocompetent for the task.
Being too competent (or over-qualified) can make the task at hand boring and mitigates your motivation to complete it.
It is therefore important that you keep your project challenging, for example by taking up other tasks to increase the workload and subsequently increasing the competence required to finish the task. And also to keep the amount of competence required for the task at a balanced level—making the task not too easy, but also definitely not too hard.
Relatedness
Finally, you should feel some sort of relatedness to the project you are completing.
If the project is miles off from your personal interests, maybe this is not the project for you. Often times however, you do not realize this until you have already committed to it. If this is the case, think of it like this: “what do I like about the project I am doing? And what can I change to make it more relatable to me?”.
If you like the methods you are using, but not the specific topic, try to change the topic to a more relatable one. If you hate the methods but really like the topic, try a different methodological approach and you might notice that you actually can find your motivation to continue working on the project again.
Going forward
So yes, the road of a PhD candidate can indeed be long and troublesome. And working on a project that you are not motivated to finish can feel like an ever-lasting journey, or even affect your mental well-being.
It is for this reason that it’s important to know in which of the three psychological needs you are lacking, and to satisfy those needs accordingly. Because at the end of the day, the biggest hardships of completing a PhD do not come from the outside: they come from within.